Circuit breaker



Oct. 24, 1939. w. M. AUSTIN 2,177,014

CIRCUIT BREAKER Filed Dec. 31, 1936 3 Sheets-Sheet l T 77 INVENTOR 2:? W7 Wa/ferM. Aw rm BY {074 Z/ ATTORNEY W. M. AUSTIN Oct. 24, 1939.

CIRCUIT BREAKER Filed Dec. 31, 1936 3 Sheets Sheet 2 Fig. Z. 23 26 INVENTOR A I l Va/ferM/Jwf/h l ATTORNEY v WITNESSES: 4 (PM Oct. 24, 1939. w, AUSTIN 2,177,014

CIRCUIT BREAKER Filed Dec. 31, 1936 3 Sheets-Sheet s aW/////7// I I l WITNESSES; i 5

m J I I45 INVENTOR M (r B3 783 Wa/fer M/zw fin ATTORNE iary arcing contacts it is particularly desirable that the breaker be capable of being tripped at Patented Oct. 24, 1939 UNITED STATES Pennsylvania 16 Claims.

My invention relates to circuit breakers in general and more particularly to circuit breakers for use in locations where they may be subjected to jarring forces and heavy vibrations.

Particular instances of the types of service in which circuit breakers used for controlling lighting, power and control circuits'are subjected to jarring forces and heavy vibrations; may be men tioned service on battleships, cruisers and the like war craft. Ordinary circuit breakers when used in such instances have opened under the jars caused by the firing'of heavy guns or when the ship strikes an object or is struck by a shell,

been severely crippled just when it is most needed. Circuit breakers have been developed for such specialized service which embody shock proof latching means for holding the breaker in closed circuit position yet which will allow the same to open in response to overloads. These specialized breakers while partially solving the problem have not embodied the much desired trip free action, i. e., the movable contacts have not been able to open irrespectiveof the position of the control handle.

In the heat of battle or on other special occasions it may be desirable to prevent the breakers from opening and disrupting service on overloads. If the breaker embodies the desirable trip free action, holding the operating handle in closed separate irrespective of the position of the control handle.

In a trip free circuit breaker embodying auxilany point in the closing operation after the arcing contacts have engaged in order to fully protect the breaker and the circuits and apparatus which it controls.

It is accordingly an object of my invention to provide a circuit breaker structure embodying an improved simple and eiiicient latching arrangement which will prevent the breaker from opening in response to jarring forces and yet which will permit opening of the breaker in "response to overload conditions.

Another object of my invention is to provide an improved circuit breaker structure embodying a simple and effective shock proof latching arthereof and in which the movable contacts of the breaker are capable'of opening upon the occurrence of overloads irrespective of the position of the operating member or handle.

Another object of my invention is to provide an improved circuit breaker structure in which the movable contacts are trip free of the operatwith the result that the electrical service has circuit position is of no avail since the contacts rangement for cooperating with the trip device PATENT OFFICE.

CIRCUIT BREAKER Walter M. Austin, Pittsburgh, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Application December 31, 1936, Serial No. 118,588

means which can be manually operated to prevent tripping of the breaker on overload.

Another object of my invention is to provide an improved circuit breaker embodying a simple shock proof latching arrangement cooperating with the trip device in which latches are so arranged that they cannot be manually reset until the circuit breaker operating mechanism is reset.

Another object of my invention is to provide 'an improved trip free circuit breaker structure that is capable of being tripped at any point in the closing operation after the auxiliary arcing contacts engage.

The novel features that I consider characteristic of my invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof will best be understood from the following detailed description of a specific embodiment thereof when read in connection with the accompanying drawings, in which Figure 1 is a front view of the circuit breaker embodying the features of my invention;

Fig. 2 is a vertical sectional view of the circuit breaker shown in Fig. 1, taken on the line 1-1 thereof and looking in the direction of the arrows;

Fig. 3 is a fragmentary view partly in elevation and partly in section and with certain parts broken away, showing the center pole contact means and parts of the operating mechanism in their closed circuit position with the latches set in latching position; Fig. 4 is a view similar to Fig. 3 showing the corresponding parts in a certain stage of the tripping operation, the movable contacts and the movable contact controlling yoke having moved to open circuit position, the latches being in their released position and the operating mechanism ready to start its movement to open circuit posi- I tion; and

Fig. 5 is a view similar to Figs. 3 and 4 showingthe corresponding parts in their-final open circuit positions following the completion of the tripping operation,

Referring to the drawings, the multi-pole circuit breaker illustrated is mounted on a base 9 of insulating material. Each pole of the circuit breaker comprises, in general, a pair of terminal studs H and IS, a frame l5, main stationary contacts l1, a/ main movable brush contact l9,

auxiliary arcing contacts 2| and 23, a pivotedvswitch arm 25, a plvoted 'actuating member 21 and an electro-magnetic trip means indicated generally at 28/ V The above-mentioned elements are identical for each pole ofthe breaker with the exception of the pivoted actuating member 21, and, coning mechanism and which is provided with a sequently, a detailed description of these ele- 5o ments for one pole only will be given. The upper terminal stud II is electrically connected to the upper main stationary contact l1 and to the stationary arcing contacts 2| and 23. The main movable contact I9 is of the semi-elliptic laminated brush type, the ends of which are adapted to engage the stationary contacts l1 to close the circuit between the same. The switch arm 25 is yoke shaped and has the lower ends of its legs pivotally supported by means of a pivot pin 3| transversely mounted between the side walls of the main frame l5. The movable arcing contacts 2| and 23 are secured to resilient switch members 26 and 33, the lower ends of which, together with the movable brush contact I9, are secured to a cross piece of the switch arm 25 by means of screws 35. The arcing contacts 2| and 23 are arranged so that they engage before the ends of the brush contact |9 engage the main stationary contacts I1 when the movable switch arm 25 is moved to closed circuit position, and arranged to separate after the ends of the brush contact l9 leaves the main stationary contacts |1 when the switch arm 25 is moved to the open circuit posi-- tion so that any are that is formed will always be drawn between the auxiliary arcing contacts. The upper ends of the legs of the switch arm 25 are pivotally connected to one end of a pivot link 31 by means of a pivot pin 39. The other end of the pivot link 31 is pivotally connected to its corresponding actuating member 21' by means of a pivot pin 4|.

The circuit for each pole of the breaker is identical and extends from the upper terminal stud H to the upper stationary contact I1 and the stationary arcing contacts 2| and. 23 to the movable arcing contacts 2| and 23, the movable brush contact l9, to the lower stationary contact I1 and flexible shunt conductor 43 to one terminal of the electromagnetic trip means 29, and through the coil thereof to the lower terminal stud I3.

The actuating member 21 for the center pole of the breaker comprises a yoke shaped lever which is pivotally supported between the upper ends of the main frame l5 by means of a. pivot pin 45. The end of the actuating member 21 to which is connected the pivot link 31 has a depending tail portion 41 upon which is mounted a trip latch mechanism which will be hereinafter described.

The actuating members 21 for the two outer poles of the circuit breaker are substantially similar to the actuating member for the center pole, with the exception that they are not provided with depending tail portions. All of the actuating members 21 are secured for simultaneous movement together by means of an insulating tie bar 49 which extends across the upper ends of the members 21 and is secured to each by means of screws 5|. It will thus be seen that movement of the center pole actuating member 21 will cause similar movements of the actuating members 21 for the outer poles of the breaker. Each of the actuating members 21 is biased in a counter-clockwise direction about its pivot pin 45 by means of a pair of springs 53, only one being shown. The springs 53 have their upper ends secured to lugs projecting from the sides of the actuating members 21, and their lower ends anchored to the sides of the main frames l5. The actuating members 21 are movable about their pivot pins 45 to open and to closed circuit position to cause the movable switch arms 25 to move to their open or to their closed circuit position to open or to close the circuits controlled by the breaker.

A common operating means is provided for moving the actuating members 21 to closed circuit position. comprises, in general, a single pivoted operating member 55, an operating rod 51,.a pivoted lever 59, an operating solenoid indicated generally at 6| and a manual operating handle 63.

The operating member 55 comprises a yoke shaped lever which is pivotally mounted between the upper ends of the frame |5 by means of the pivot pin 45. The sides of the yoke shaped operating lever are spaced apart a suflicient distance to permit the center pole actuating member 21 to lie between the same in the open circuit position of the actuating member 21, as shown in Fig. 4. The lower end of the operating lever 55 is provided with a cross piece 65 (Figs. 3-5) to which is secured a latch piece 51 adapted to be normally engaged by the latch mechanism carried on the depending tail portion of the center pole actuating member 21, the said latching mechanism which will hereinafter be described in detail is adapted to normally connect the center pole actuating member 21 to the operating member 55 for movement therewith. The operating member 55 is provided with a pair of parallel outwardly projecting curved legs 69 having aligned openings 1| to receive a pivot pin 13 which pivotally connects the operating member 55 to the upper end of the operating rod 51, as shown more clearly in Figs. 1 and 2. The lower end of the operating rod is pivotally connected by means of a pivot pin 15 to one end of the lever 59. The lever 59 is, in turn, pivotally supported by means of a fixed pivot pin 11 carried by the lower end of a frame 19 for the operating solenoid 6|. The end of the lever 59 opposite that to which is connected the operating rod 51 is pivotally connected by means of a pivot pin 8| to one end of the movable core 83 of the operating solenoid 6|.

The manual operating handle 63 is provided with a handle portion 85 at its upper end and its lower end is bent in the form of a U, which is provided with aligned openings for mounting the same on the fixed pivot pin 11, as best shown in Fig. 1. The bight 81 of the lower U-shaped portion is adapted to engage and move that end of the lever 59 which is connected to the movable core 93 of the solenoid, when the operating handle 63 is rotated in a clockwise direction about its pivot pin 11. It will thus be seen that the operating member 55 and the normally connected actuating members 21 may be moved 5 clockwise about their pivot pins 45 to their closed circuit position either by means of the operating solenoid 5| or by manual clockwise rotation of the operating handle 63.

The operating member 51 is biased upwardly 6 to open circuit position by means of a main spring 89, the upper end of which is anchored to the frame 19 of the operating solenoid 5| and the lower end of which is connected to the pivot pin 15. The main spring 89 biases the operating 65 rod 51 upwardly and exerts an upward thrust on the pivot pin 13 to bias the operating member 55 in .a counterclockwise direction about the pivot pin 45 toward its open circuit position, the full open circuit position of the operating mem- 7 ber 55 being shown in Fig. 5.

Since both the operating member 55 and the normally connected center pole actuating member 21 are biased counter-clockwise about their pivot pin 45 to their open circuit position, some 7 The common operating means 5 means must be provided for holding the operating member in closed circuit positionafter it has been moved to such position by either the operating solenoid 6| or the operating handle 63.'. The meansfor holding the operating member 55 and the normally connectedj actuating member 21 in closed circuit position comprises a pivoted latch member 9| which is pivotally mounted on the main frame by means of a pivot pin 93. The latch member 9| is provided with a latch shoulder 95 (see Fig.4) for engaging the cross piece 65 of the operating member 55 in the latching position of said latch member.

The electromagnetic trip means for the center pole of the breaker is provided with a pivoted trip lever 91 which is pivotally mounted on the pin 93 which supports latch member 9I. The trip lever 91 is biased to a normal position against the upper end of the electromagnetic trip means by means of a light spring 99, which has its lower end secured to a depending projection I 01 formed on the trip lever 91 and has its upper end secured to the upper end .of the pivoted latch member 9|. The spring 99 thus biases the trip' lever 91 to its normal position, as shown in Fig. 3 and also biases the latch member St to its latching position,'. also shown in Fig. 3. The electromagnetic trip means for the two outer poles of the breaker are also provided with trip levers similar to the trip lever,

91 of the center pole. The trip levers for all the poles are mechanically connected for simultaneous movement together by means of a trip bar I03 which extends across the upper ends of the trip levers 91 and is secured to each by means of screws I05 so that operation of any of the electromagnetic trip means will cause simultaneous movement of the mechanically connected trip levers 91 to their tripping position.

' Referring to Figs. 3, 4 and 5, the trip latch mechanism which normally connects the center pole pivoted actuating member 21 with the pivoted operating member 55 comprises a main latch member I01 and a cooperating auxiliary latch member H0. The latch member I01 is pivotally mounted on a pivot pin I09 which extends transversely between the legs of Y the .depending tail portion 41 of the yoke shaped actuating member 21. The head III of the latch member is provided with a recess forming a pair of oppo'sitely disposed shoulders which engage the latch piece 61 of the operating member 55 in the latching position of the main latch member I01, as shown in Fig. 3. The latch member I01 has a projecting arm fll3 which is adapted to be en gaged and held in latched position by the hook shaped end II of the auxiliary latch member I 10. The auxiliary latch member I I0 is pivotally mounted on a pivot pin I I1 which extends transversely between the legs of the tail portion 41 of the actuating member 21, and has a depending tail portion II'9. =The auxiliary latch member H0 is biased to latching position in which its hook-shaped end II5 engages and holds the main latch member I01, by means of a coiled compression spring I2I which is disposed in a recess formed in a cross piece I23 of the tail portion 11 of the actuating member 21. The

main latch member I01 is biased to releasing position by means of a light coiled compression spring I25 seated in a recess in the cross-piece The auxiliary latch member IIO has a relatively light mass as compared with the mass of the main latch member I01 and the spring I2 I is relatively strong so that the auxiliary same.

tion in response to jarring forces or heavy vi-s brations applied to the base or the breaker;

The tail portion II9 of the auxiliary latch member H0 is adapted to cooperate with a projection I21 formed integral with the trip member .91 of the center pole of the breaker so that when the trip member 91 of the center pole or the connected trip members 91 of either of the outer poles are moved to tripping position, the projection I21 engages the end of the tail portion H9 and moves the latch member IIO in a counter-clockwise direction about its pivot pin II1 to its releasing position in which the hookshaped end II5 disengages the long arm III of the main latch member I01 to release the When the main latch I01 is released, it is partially rotated in a clockwise direction about its pivot pin I09 by the bias of the spring I25 and by a component of the force exerted on the actuating members I21 by the biasing springs 53. When thelatch member I01 is thus moved after release. it removes the left-hand shoulder of its head I II from engagement with the latch piece 61 of the-operating member 55 to eifect sition following release thereof, the actuating members 21 tor the outer poles of the breaker also move to their open circuit positions. The

movement of the actuating members 21 to their open circuit position causes simultaneous movement of all of the switch arms 25 and movable contacts to their open circuit position to interrupt the circuits controlled by the breaker. I

It will be noted that when; the center. pole actuating member 21 has been moved to open circuit position following a tripping operation. the main and auxiliary latches cannot be reset by reason of the fact that the auxiliary latch member H0 is held in its rele ed position by the engagement of its tail porti H9 with the cross piece 55 of the operating member 55 as shown in Fig. .4, .while'said operating member is in its closed circuit position. This is a particularly desirable feature since if the latches are manually reset when the actuating members 21 are in their open circuit position, the parts may become jammed when the operating member 55. is released tion.

The tail portion 01 of the center pole actuating member 21 is provided with a cam surface I29 which, during movement of the actuating member to open circuit position following the release or the same, engages and moves the latch member 9| to its rel eased position, as shown in Fig. 4. The movement 0! the'latch member 9I to its redeasing position causes the shoulder 95 thereof to be removed from its engagement with the 29d moves to its open' circuit; position, the latch piece 61 engages the right hand shoulder provided in the head III of the main latch member I01 and moves the latch member in a counter-clockwise direction about its pivot pin I09 to latching position to reengage the end of the long arm II3 under the hook-shaped end I I5 of the auxiliary latch member I I thus reset ting the latch members and reestablishing the mechanical connection between the center actuating member 21 and the operating member 55. The breaker is now in reset and in open circuit position, and can be closedagain either by energization of the operating solenoid BI or by manually rotating the operating handle 63 in a clockwise direction.

When the operating member and normally connected actuating member 21 have been moved to their closed circuit position, the latch member 9I reengages its shoulder 95 with the cross piece 65 to latch the breaker in its closed circuit position. It will be noted that the point of engagement of the cross piece 55 of the operating member with the shoulder 95 of the latch member 9I is so posi tioned with respect to the pivot pin 93 of the latch member 9I, that the force exerted by the springs 53 and also by the main spring 89 biases the latch member with a strong force to its latching position thus rendering the latch member 9I substantially shock-proof so that it will not be moved to released position in response to jarring forces or heavy vibrations applied to the base of the breaker. In order for the breaker to be tripped openby the release of the latch member 9| by a jarring force, it would be necessary for the operating member 55 to be movedpast its closed circuit position, which is highly improbable, due to opening force exerted by'the combination of the springs 53, the spring 89 and the relatively stiff resiliency of the contact brush I9.

The overload electromagnetic trip means for each pole of the breaker for moving the trip members 91 to tripping position comprises a solenoid coil I3I, a stationary core I32, and a movable solenoid core I33. The movable core I33 has an extending pin I35 secured thereto which extends through an opening in the frame I5. The upper end ofthe pin I35 normally lies flush with the upper surface of the frame I5.- When a current of predetermined magnitude flows through the solenoid coil I3 I, the magnetic force developed is suflicient to move the core I33 and pin I35 in an upward direction to cause the pin to engage its trip member 91 to move the same to tripping position, during which movement the projection I21 of the center pole trip member engages and moves the auxiliary latch member IIO to releasing position. Each of the overload electromagnetic trip means 29 is provided with a suitable adjustable oil dashpot device I36 for providing a predetermined time delay between the occurrence of an overload and the tripping operation. The device I36 may also include a suitable means for adiusting'the air gap between the stationary core I32 and the movable core I33 to, adjust the trip characteristic of the trip means.

An electromagnetic shunt trip means I31 is provided for electrically tripping the breaker.-

The shunt trip means I31 comprises a solenoid winding I39 and a solenoid core I to which is secured an adjusting screw I43. The shunt trip means 131 is mounted on a U-shaped bracket I45 secured to one of the frames I5. The trip bar I03 that connects the trip members 91 has an angular plate I41 secured thereto which is adapted to be engaged by the adjusting screw-l43 when the electromagnetic shunt trip is energized to move the trip members to their tripping position.

A manual control handle I49 is also secured to the trip bar I03 so that the tripping members 91 may be manually moved to tripping position to trip the breaker.

In certain instances, such .as in the heat of battle, it may be desirable to prevent the breaker from tripping open in response to overload conditions. For this purpose a manually controlled trip preventing means is associated with the electromagnetic trip means 29 of each pole of the breaker. The manually controlled overload trip preventing means comprises a plurality of pins II, one for each pole of the breaker, which .extend through openings provided therefor in the base 9. The right hand ends of the pins I5I normally lay to the left of and out of the path of the pins I35 of the electromagnetic overload trip means 29. The left hand end of the pins I5I are pivotally connected to a plate I53 which extends transversely across the base 9 and which is pivotally secured to the brackets I55 mounted on the base 9. One end of the plate I53 is provided with an extending leg I54 to which is pivotally connected an operating rod I51 which is adapted to project through an opening provided in the conventional mounting panel I59. A coil compression spring I50 is mounted on the rod I51 and is held in compressed condition between a collar I58 on the rod I51 and the panel I59 to bias the rod I51 to inoperative position. If it is desired to prevent tripping of the circuit breaker on overload, the rod I51 is pulled outwardly which rocks the plate I53 and causes the ends of the pins I5I to be interposed between the ends of the pins I35 of the electromagnetic overload trip means 29 and their corresponding trip levers 91, so that even though an overload occurs, the movable cores I33 cannot move their trip levers 91 to tripping position.

An auxiliary or interlock switch I 6| is mounted on the base and is adapted to be sequentially operated by operation of the circuit breaker by means of a link connection I63 which connects the auxiliary switch control lever I55 with the pin 8| connecting the lever 59 with the movable core 83 of the operating solenoid 6|. The auxiliary switch I5I is thus adapted to be operated with each operationof the circuit breaker.

The operation of the circuit breaker is briefly as follows. With the parts of the breaker in the position shown in Fig. 2, letit be assumed that an overload occurs in the circuits of any one of the poles of the circuit breaker. The electromagnetic overload trip means 29 of tlrie pole on which the overload occurs draws up its movable core I33 and causes its pin- I35 to engage and move its trip member 91 to tripping position. The movement v The release of the main latch member I01 allows the mechanically connected actuating members 21 to move to their open circuit position under the influence of their biasing springs 53. As the center pole actuating member 21 moves toward 1% open circuit position, the cam surface I29 thereof engages and moves the latch member M to its releasing position to effect release of the operating member 55. When the operating member, is released, the, main spring 09 causes the same -55. The breaker may be tripped open in the same manner as described above in connection with the overload tripping operation, by manually moving the trip bar I 03 to tripping position or by energizing the electromagnetic shunt trip means The breaker may be closed by energizing the operating solenoid 6| or by moving the operating handle 63 in a clockwise direction about the pivot pin 11. Either one of these operations causes the operating rod to move downwardly to effect clockwise rotation of the normally mechanically connected center pole actuating member 21 and operating member 55 to their closed circuit position in which the operating member 55 is held latched by means of the latch member 9 I. The movement of the center pole actuating member 21 to closed circuit position effects simultaneous movement of the actuating members 21 of the outer poles of the breaker toieffect movement of all of the movable contacts to their closed circuit position. It

'of the fact that the tail piece of the auxiliary latch member I III is of such length that some part of it is in position to be engaged by the projection I21 on the center pole trip member 91 during closing movement of the actuating and operating members.

When the circuit breaker is mounted for service on a battleship or the like war craft it may be desired, during the heat of battle or for some other particular purpose, to prevent an overload occurring in any or all poles of the circuit breaker from automatically tripping the breaker to open circuit position. To prevent such automatic tripping, it is merely necessary to pull out the manual trip preventing rod I51. Pulling out the control rod I51 causes all of the pins l5| which it controls to be interposed between all of the overload solenoid operated pins I35 and their corresponding trip levers 91.

It will thus be seen that I have provided an improved trip free circuit breaker structure emof the actuating'member and operating member prevents the latches from being reset except by resetting of the breaker operating mechanism and permits the breaker tobe tripped to open circuit position at any point in the closing operation after the auxiliary arcing contacts have engaged. I have also provided an improved circuit breaker which embodies a means which can be manuallyheldto prevent tripping of the breaker on overload when it is desired to prevent interruptions of the electrical circuits controlled by the breaker.

While I have shown and described the preferred embodiments of my invention in accordance with the patent statutes, it is to be understood that various changes in the structural details may be made without departing from the spirit of the invention. I desire, therefore, that the invention be limited only by the reasonable construction of the appended claims and the prior art.

I- claim as my invention:

1. In a circuit breaker, a movable circuit con trolling member biased to open circuit position, a movable operating member biased to open circuit position, a first latch means for normally connecting said circuit controlling member to said operating member for movement therewith, means for moving said operating member and through the same said normally connected circuit controlling member to closed circuit position, a second releasable latch means for normally holding said operating member in its closed circuit position, means for releasing said first latch means to allow said circuit controlling member to move to open circuit position, said circuit controlling member having means for releasing said second latch means during movement to open circuit position to allow said operating member to move to open circuit position, the movement of said operating member to its open circuit position resetting said first latch means to reestablish connection of said circuit controlling member to said operating member, and means associated with said latch means for preventing release of either of said latch means in response to jarring forces or vibrations. g

2. In a circuit breaker, a pivoted switch member biased to open circuit position, an operating member pivoted about the same axis as said switch member and biased to open circuit position, a first releasable latch means for normally connecting said switch member to said operating member for movement therewith, means for moving ;said operating member and normally connected switch member to closed circuit position, a second releasable latch means for normally holding said operating member in its closed circuit position, means for releasing said first latch means in response to predetermined overload conditions to allow said switch member to move to its open circuit position, said switch member having means for releasing said second latch means during movement toward its open circuit position to allow said operating member to move to its open circuit position, said operating member during the last part of its opening movement causing resetting of said first latch means to reestablish connection of said switch member to said operating member, and means associated with both said latch means for preventing release thereof in response to jarring forces or vibrations applied to said breaker.

3. In a multi-pole circuit breaker, a plurality ofpivoted circuit controlling members forming a plurality of poles, means connecting said members for simultaneous movement together, means biasing said members to open circuit position, a common operating member pivoted about the same axis as said members, means biasing said operating member to open circuit position, a first releasable latch means fornormally connecting one of said circuit controlling members to said operating member for movement. therewith;

means for moving said operating member, and through said member the normally connected circuit controlling members to closed circuit position, a second releasabledatch means for holding said operating member closed circuit 7 position, a trip device comprising a plurality of mechanically connected trip elements, one for each pole of the breaker, each responsive to predetermined overload conditions in the circuit 01' its pole for causing said trip device to effect release of said first latch means to allow said circuit controlling members to move to their open circuit position irrespective of the position of said operating member, said one circuit controlling member acting to release said second latch means during movement to open circuit position to allow said operating member to move to its open circuit position, said operating member when moved to open circuit position efiectingresetting of said first latch means to reestablish the normal connection of said circuit controlling members to said operating member, and means cooperating. with both of said latch means for preventing release of said latch means in response torjarring forces and vibrations applied to said breaker.

4. In a multi-pole circuit breaker, 'a plurality of pivoted circuit controlling members forming a plurality of poles, means connecting said members for simultaneous movement together, means biasing said members to open cir t' P it on. a common operating member pivoted about the same axis as said members, means biasing said operating member to open circuit position, a first releasable latch means for normally connecting one of said circuit controlling members to said operating member for movement 1 therewith, means for moving said operating member, and through said member the normally connected circuit controlling members, to closed circuit position, a second releasable latch means for holding said operating member in closed circuit position, a trip device comprising a plurality of mechanically connected trip elements one for each pole of the breaker, each responsive. to predetermined overload conditions in the circuit of its pole for causing said trip device to effect release of said first latch means to allow said circuit controlling members to move to their open circuit position irrespective of the position of said operating member, manually operable means for releasing said first latch means, said one circuit controlling member acting to release said second latch means during movement to'open circuit position to allow said operating member to move to its open circuit position, said operating member when moved to open circuit position efi'ecting resetting of said first latch means to reestablish the normal connection of said circuit controlling members to said operating members, and means cooperating with both of said latch means for preventing release of said latch means in response to jarring forces and vibrations applied to said breaker.

5. In a circuit breaker, a movable circuit controlling member biased to open circuit position, a movable operating member biased to open circuit position, a first releasable latch means for normally coupling said circuit controlling member to said operating member for movement thereby, operating means for moving said operating member and normally connected circuit controlling member to closed circuit position, a second releasable latch means for normally holding said operating member in closed circuit position, a trip device operable in response to predetermined overload conditions in the circuit controlled by the breaker for releasing said first latchmeans to allow said circuit controlling member to move to its open circuit position, said circuit controlling member in moving to open circuit position efiecting release of said second latch means to allow said operating member to 6. In a circuit breaker, a movable circuit con-,

trolling member, means biasing said member to open circuit position; a movable operating member, means biasing \said operating member to open circuit position, a first releasable latch means for normally connecting said circuit controlling member to said operating member ,ior

movement thereby, operating means for moving said operating member and normally connected circuit controlling member to closed circuit position, a second releasable latch means for normally holding said operating member in closed circuit position, means for releasing said first latch means to allow said circuit controlling member to move to its open circuit position, said circuit controlling member in moving to open circuit position efiecting releaseof said second latch means to allow saidoperating member to move to its open circuit position, said operating member when moved to its open circuit position eflecting automatic resetting of said first latch means to reestablish connection between said circuit controlling member and said operating member, means for preventing'resetting of said first latch means except by movement of said operating. member to open circuit position and means for preventing resetting of said second latch means until said operating member moves to closed circuit position.

7. In a circuit breaker, a pivoted circuit controlling member movable to open and to closed circuit position to open and to close the circuit, means biasing said member to open circuit position, an operating member pivoted about the same axis as said circuit controlling member and biased to open circuit position, a pivoted main latch carried by said circuit controlling member having a latching position for engaging a cooperating latch piece carried by said operating member for OOH? necting said circuit controlling member to said operating member for movement thereby, an auxiliary pivoted latch carried by said circuit controlling member biased to latching position in tion, the movement of said member to its open circuit position eflecting movement or said second latch to releasing position to allow said operating member to move to its open circuit position, said operating member when so moved to its open circuit position eflecting automatic resetting of said main and auxiliary latches to reestablish connection between said circuit controlling member and said operating member and means for preventing resetting of said main and auxiliary latches except by the resetting opening movement of saidoperating member.

8. In a circuit breaker having main relatively movable contacts and cooperating auxiliary arcing contacts-which open after the main contacts open and close before the main contacts close, a pivoted actuating arm connected to said contacts for moving the same to open and to closed circuit position, means biasing said actuating arm to open circuit position, an operating member pivoted about the same axis as said arm, a pivoted main latch carried by said arm having a latching position in which it engages a latch piece carried by said member, a second latch pivotally supported by said arm having a latching position to which it is biased for engaging and holding said main latch in latching position for normally connecting said arm to said member for movement therewith, operating means for moving said member and normally connected arm to closed circuit position, a tail piece carried'by said second latch, a trip device including a trip member movable in response to predetermined overload conditions to engage and move said tail piece to release said latches and allow said arm to move to open circuit position irrespective of the position of said operating member, means for moving said operating member to open-circuit position following release of said arm, said latch piece effecting resetting of said latches when said member is moved to open circuit positionto reestablish the normal connection of said arm to said member, said tail piece being of a length to permit said trip member to release said latches at any point in the closing movement of said arm and member after said arcing contacts engage. g

9. In a circuit breaker, a stationary contact, a cooperating movable contact carried by a pivoted switch arm, a pivoted actuating member connected to said switch arm by a pivot link and movable to an open and to a closed circuit position to open and to close said contacts, means biasing said member to open circuit position, latch mechanism for releasably holding said member in closed circuit position comprising a main latch member pivotally mounted on a'portion of said 50" arm for engaging a fixed cooperating latch piece in its latching position, an auxiliary latch member of relatively small mass pivoted on said portion of said arm, having a latching position in which it engages and holds said main latch memher in latching position to hold said actuating member in closed circuit position, a relatively strong spring for biasing said auxiliary latch member to its latching position so that it is rendered substantially shockproof, a trip device operable to move said auxiliary latch member to releasing position to release said main latch member and allowsaid actuating member to move to its open circuit position in which said portion and said latch members are moved out of the way of said switch arm and movable contact.

10. In a circuit breaker, a stationary contact, a pivoted switch arm carrying a cooperating movable contact, a pivoted actuating member pivotally connected tov said arm and being movable to open and to closed circuit position to open and to close said contacts, means biasing said member to open circuit position, an operating member pivoted about the same axis as actuating member, a releasable latch mechanism for normally connecting said members for movement together comprising a main latch member pivoted on a portion of said actuating member having a latching position in which it engages a latch piece carried by said operating member, an auxiliary latch member of relatively light mass pivoted on said portion of said actuating member having a. latching position in which it engages and holds said main latch member in its latching position to connect said actuating member to said operating member, a relatively strong spring for biasing said auxiliary latch member to its latching position whereby said latch member is rendered substantially shock proof, means for moving said operating member and normally connected actuating member to closed circuit position and releasably restraining said operating member in said position, a trip device operable to move said auxiliary latch member to releasing position to release said main latch member and allow said actuating member to move to, its open circuit position, the said portion of said member and said 'latch members being moved out of the way of said switch arm and movable contact when said actuating member moves to open circuit position.

11. In a circuit breaker having relatively movable contacts, the combination of a pivoted actuating member movable to open and to closed circuit position to open and to close said contacts, a first spring means for biasing said member to open circuit position, an operating member pivoted about the same axis as said'actuating member and biased in the same direction to open circuit position by a second spring means, releasable latch means having a latching position for normally connecting said members for movement together, means for rendering said latch means substantially shock proof so that jarring forces or vibrations applied to the breaker will not release the same, means or moving said operating member, and through the same said normally connected actuating member, to closed circuit position, a pivot latch member having a latch face for engaging a cooperating latch face on said operating member in the closed circuit position of the same for holding said member in said closed circuit position, a relatively light spring for biasing said latchmember to latching position, the point of engagement of said latch faces being so located with respect to the pivot axis of said latch member that said spring means biases said latch member to latching position to render said latch member substantiallfshock proof, a trip device operable in response to predetermined overload conditions to release said latch means to allow said actuating member to move to open circuit position during which movement said member moves said latch member to releasing position to allow, said operating member to move to open circuit position, said operating member when moved to open circuit position efiecting resetting of said latch-means to reestablish the normal connection between said actuating member and said operating member. 7

12. In a circuit breaker having stationary main and arcing contacts and a pivoted switch arm carrying cooperating movable main and arcing contacts, a pivoted contact controlling member pivotally connected to said switch arm and movable to open and to closed circuit position to open and to close said contacts, means biasing said member to open. circuit position, an operating member pivoted about the same axis 'as said contact controlling member and biased to open circuit position, a mainlatch member pivoted on said contact controlling member and having arms of of oppositely disposed shoulders for engagement with a latch piece carried by said operating member, an auxiliary latch member of relatively small mass pivoted on said contact controlling member having a latch portion for engaging and holding the longer arm of said main latch to hold the same in latching position in which it normally connects said contactcontrolling member to said operating member for movement therewith, said auxiliary latch member having a tail piece, a spring for biasing said auxiliary latch member to latching position .with a relatively large force whereby said auxiliary latch member is rendered substantially shock proof, means for moving said operating member and normally connected contact controlling member to closed-circuitposition, a second pivoted latch member having a latch race for engaging a shoulder-formed on said operating member for holding the same in closed circuit position, a light spring for biasing said second latch member to latching position, the point of engagement betweensaid latch face and said shoulder being so located with respect to the'pivot axis of said second latch member that the biasing forces of said normally connected members tending to move the same to their open circuit position biases said second latch member to its latching position so that it is rendered substantially shock proof, a trip device including a trip member movable in response to predetermined overload conditions to engage the tail piece of said auxiliary latch to move'the same to releasing position to allow said contact controlling member to move to open circuitposition in which said main and auxiliary latch members are out of the way of said switch arm; said member in moving to open circuit position effecting release of said second latch member, to allow said operating member'to move to open circuit position, the latch piece on said operating member during the latter part of said opening movement engaging and moving one of the shoulders on the short arm of said main latch to efiect resetting of said main and auxiliary latches to reestablish connection between said contact controlling member and said operating member, said tail piece of said auxiliary latch engaging. said latch piece on said operating member when said contact controlling member is in open circuit position to prevent resetting of said main and auxiliary latches except bymovement of said operating member to open circuit position, said tail piece also providing a means whereby, said trip member can release said auxiliary latch at any point in the closing movement of said contact controlling and operating members after the arcing contacts engage.

13. In floCil'Cllit breaker, a movable circuit controlling member biased to open circuit position, an independently movable operating member for moving said circuit" controlling member to open and to closed circuit position, shockproot latch means for normally connecting said circuit'controlling member to said operating member for movement thereby comprising a pivoted main latch member carried by one of said members for engaging a cooperating latch piece carried by the other of said members in its latching position, a pivoted auxiliary latch member of relatively small mass carried by said one member having a latch ing position in which it engages and holds said main latch member in latching position and a relatively strong spring for biasing said auxiliary latch member to its latching position; and a trip ating member.

2,177,014 different length, the shorter of which has a pair device operable to release said latch means to allow said actuating member to move to its open circuit position.

14. In a multiple circuit breaker, a plurality of movable circuit "controlling members connected for movement together and forming a plurality oi poles, means biasing said members to open circuit position, a common movable operating member biased to open circuit position, a first releasable latch means for normally connecting said circuit controlling members to. said operating member for movement thereby, means for moving said operating member and through said member the normally connected circuit controlling members to closed circuit position, a. second releasable latch means for holding said operating member in closed circuit, position, a trip device operable to eflect release of said first latch means to allow said circuit controlling members to move to open circuit position irrespective of the position of said operating member, saidmembers being operable during movement to open circuit position to release said second latch means to allow said operat-- ing member to move to open circuit position, said operating member when moved to open circuit position effecting resetting of said first latch means to reestablish the connection between said .circuit controlling members and said operating member, and means rendering both of said latch means shockproof to prevent their release by Jarring forces and vibrations.

15. In a circuit breaker, a movable circuit controlling member biased to open circuit position, a movable operating member biased to open circuit position, a first latch means for normally connecting said circuit controlling member to said operating member for movement therewith, means for moving said operating member and through the same said normally connected circuit controlling member to closed circuit position, a second releasable latch means for normally holding. said operating member in its closed circuit positiommeans for releasing said first latch means to allow said circuit controlling member to move to open circuit position, said circuit controlling member having means for releasing said second latch 'meansdur ing movemeht to open circuit position to allow ,said operating member to move to open circuit position, the movement of said operating member to its open circuit position resetting said first latch means to reestablish connection of said circuit controlling member to said operating member.

other of said members in its latching position, a

pivoted auxiliary latch member of relatively small mass carried by-said one member having a latching position in which it engages and holds said main latch member in latching position, and a relatively strong spring for biasing said auxiliary latch member to its latching position; and a trip device operable to release said latch means to allow said actuating memberto move to its open circuit position irrespective of the position of said oper- WAL'I'ER M. AUSTIN. 

